Some news about my problem.
Fiasco catches an exception (it seems to be a page fault) into
Thread::do_ipc function (do_ipc + 0xbd). As there are many inline
functions, I decided to remove INLINE option to fiasco kernel. And...
no more exception :/.
Now ovlscreen driver works perfectly.
It seems that there is a bug, but I don't know if it is due to PIC (I
tried to come back to gcc 3.4.4 without success) code or to a fiasco
bug for long IPC ? Any idea ?
If you want more info, I can give you or I can do some experiment.
Regards
Marc